( )和其自然特性是土地所具有的特性。
A．计划经济 B．社会经济 C．商品经济 D．市场经济
参考答案：B
石油沥青的牌号越大，则其( )
A．针入度越小 B．延度越小C．软化点越低 D．粘度越大
The students in Class Two played basketball against Class One yesterday, _______? [ ]
A. did they
B. didn't they
C. weren't they
